Breastfeeding little Maxwell, now 3 months, Simpson (a well-known fan of the margaritas at high-end Mexican chain Dos Caminos) has more than one reason to eschew too much booze: Having inked a deal with Weight Watchers, she has until the end of August to lose 20-30 pounds of the estimated 70 she gained while pregnant with her first child.

"Jessica has always had issues with junk food," an insider told Us Weekly of the star, who's training again with celeb coach Harley Pasternak.

"[Weight Watchers] focuses on healthy habits for the long-term (and I can still indulge in my guilty pleasures every now and then, too)," the new mom explained on Facebook. "I have actually gotten a group of friends together who are going to be doing it with me."